Estimation for hidden Markov random fields

A finite state Markov random field is noisily observed via a second finite state process. The parameters of the model are estimated, as well as the most likely signal given the observations.     

燃烧诱发的炉墙结构振动

本文根据实测得到的国产300MW锅炉燃烧压力场功率谱密度函数,研究了用计算方法估计由燃烧诱发的结构振动,并与用实测方法获得的振动值作了对比,结果很接近。从而证明计算所用的数据与方法是可靠的。     

Saddlepoint approximations for some models of circular data

In this article we provide saddlepoint approximations for some important models of circular data. The particularity of these saddlepoint approximations is that they do not require solving the saddlepoint equation iteratively, so their evaluation is immediate. We first give very accurate approximations to P-values, critical values and power functions for some optimal tests regarding the concentration parameter under wrapped symmetric α-stable and circular normal models. Then, we consider an approximation to the distribution of a projection of the two-dimensional Pearson random walk with exponential step sizes.     

“森林有害生物控制”教学改革理论与实践

作者针对“森林有害生物控制”课程的特点,将原属于“森林昆虫学”和“林木病理学”两门课程的内容全面整合;进一步改革教学方法,通过使用多媒体技术,提供翔实生动的多媒体资料,提高学生学习的兴趣;充分利用网络工具,增加学生获取信息的途径,体现学生学习的主体地位,增强学生的自学能力;通过教学活动的全程控制,提高学生学习的主动性和积极性。     

Using sibling data to understand the impact of family group decision-making on child welfare outcomes

Few studies have examined the impact of family group decision-making (FGDM) on child welfare outcomes. Studies in this area have often suffered from small sample sizes and lack of adequate comparison groups. Since FGDM is administered at the family level, sibling data provides an ideal way to compensate for small sample sizes and low enrollment rates in research evaluating FGDM. This study utilized sibling data from California's Title IV-E Waiver Demonstration Project Evaluation in Fresno and Riverside Counties to compare child welfare outcomes for children of families randomly assigned to receive FGDM (Fresno County, n = 110; Riverside County, n = 87) to children of families assigned to receive traditional child welfare services (Fresno County, n = 74; Riverside County, n = 52). After controlling for clustering effects using general estimating equations (GEE), group differences in child maltreatment, placement stability, and permanence were modeled using linear and logistic regression. Outcomes from both counties suggested no group differences. Though neutral outcomes on child welfare indicators may bring into question FGDM's efficacy for changing child welfare outcomes, this study confirms previous findings with smaller sample sizes on the impact of FGDM and demonstrates a methodological improvement over individual or family-case analyses.     

Likelihood Estimation for Censored Random Vectors

This article shows how to construct a likelihood for a general class of censoring problems. This likelihood is proven to be valid, i.e. its maximizer is consistent and the respective root-n estimator is asymptotically efficient and normally distributed under regularity conditions. The method generalizes ordinary maximum likelihood estimation as well as several standard estimators for censoring problems (e.g. tobit type I-tobit type V).     

Model and design correspondence in finite population sampling

A correspondence rule is suggested for the choice of a sampling design when prior knowledge concerning a finite population is available. Designs satisfying the correspondence rule are discussed in the case of random permutations models. A general optimality theorem is given for strategies under such models. Approximate correspondences satisfied by systematic sampling and πps sampling are also indicated.     

On random variate generation for the generalized hyperbolic secant distributions

We give random variate generators for the generalized hyperbolic secant distribution and related families such as Morris's skewed generalized hyperbolic secant family and a family introduced by Laha and Lukacs. The rejection method generators are uniformly fast over the parameter space and are based upon a complex function representation of the distributions due to Harkness and HarknessThe author's research was sponsored by NSERC Grant A3456 and FCAR Grant 90-ER-0291.     

关于鲁迅与陈独秀等“随感录”的比较

本文通过对鲁迅与陈独秀等人《随感录》的比较，分析了他们在《随感录》内容指向、提炼与构思、文风特征及艺术品性等方面的诸多差异，对比性显示了鲁迅关注中国现实问题的独异视角和艺术上的独特创造     

The random robin problem for laplace's equation

A random generalized solution to the Robin problem for Laplace's equation is defined in terms of the sections of the random boundary data. Existence, uniqueness, and properties are established for such a solution. Particularizations to the Dirichlet and Newmann problems as well as generalization to the Robin-Poisson problem are mentioned. Applications of the results are provided.